CALIBAN Measurements Near Delayed Critical Using Subcritical Measurement Methods

摘要

The CALIBAN reactor is an unreflected highly enriched metal fast burst reactor located at the CEA Valduc center in France. Measurements were performed in June 2012 with neutron detectors consisting of He-3 tubes embedded in polyethylene near the CALIBAN assembly. In total, 17 configurations were measured: 13 were subcritical, two were at delayed critical, and two were above delayed critical. Multiple configurations at different reactivity states were obtained by varying the safety block and control rod positions. Two different detector positions were used. The neutron data that were produced were used to approximate the multiplication of each measured configuration. These measurements are particularly useful to compare with a known benchmarked system in which one can assess the reactivity and multiplication using a number of methods. The focus of this work is on the configurations near and above delayed critical, a regime in which subcritical measurement methods are not commonly used.